What came first?

Seema Hari, Noriko Misra, Vaidyanath Venkitasubramanian, & me
This assignment was a lot of fun.  We built a rectangular linkage and attached to a servo which oscillated in a 65 degree space.  We came to this number mostly by trial and error, starting with 90 and then narrowing down. 
Short video of working cuckoo: https://www.sparkcamera.com/v/2mumPwI0Kr

Longer and arguably more entertaining video: https://www.sparkcamera.com/v/zBPH3v8FpB

// Sweep

// by BARRAGAN <http://barraganstudio.com> 

// This example code is in the public domain.

#include <Servo.h> 

Servo myservo;  // create servo object to control a servo 

                // a maximum of eight servo objects can be created 

int pos = 45;    // variable to store the servo position 

void setup() 

{ 

  Serial.begin(9600);

  myservo.attach(7);  // attaches the servo on pin 9 to the servo object 

} 

void loop() 

{ 

  for(pos = 165; pos > 100; pos -= 1)  // goes from 0 degrees to 180 degrees 

  {                                  // in steps of 1 degree 

    myservo.write(pos);              // tell servo to go to position in variable 'pos' 

    delay(15);                       // waits 15ms for the servo to reach the position 

  } 

  for(pos = 100; pos<=165; pos+=1)     // goes from 180 degrees to 0 degrees 

  {                                

    myservo.write(pos);              // tell servo to go to position in variable 'pos' 

    delay(15);                       // waits 15ms for the servo to reach the position 

  } 

  Serial.println(pos);

  delay(1500);

}